HELP stereo won't work

Ok, we just got done hookin up a system on my buddys 2000 Z28 and now it won't work. Everything seems fine there just is no sound coming out of the speakers. We even disconnected the sub and it still won't work. All we did was add one subwolfer. What is wrong here.

Aftermarket deck?

We're gonna need more info. List the gear and wiring strategy and that will help us to help you diagnose the problem.

(In mentally challenged voice) Help me help you :p!

yup, need more info. is it stock, if so, are you using a line converter? if aftermarket, we'll open up another can of worms with that one.